Background: In edaravone Study 19, patients with amyotrophic lateral sclerosis (ALS) experienced significantly less functional decline with edaravone vs placebo. In addition, a previous post hoc analysis of Study 19 revealed that ALS patients with reduced forced vital capacity (FVC) of <80% prior to starting edaravone, received a significant benefit after initiating treatment (33% difference; n=25). This study included both limb and bulbar-onset patients, therefore it was important to compare these groups regarding their response to edaravone treatment, and to assess bulbar patients with FVC ≥80% vs <80% at the time of treatment initiation.
Objective: To address the efficacy of edaravone in patients with bulbar-onset ALS and those bulbar patients with FVC of either ≥80% or <80%.
Approach: Post hoc analysis of Study 19 comparing edaravone efficacy in patients with bulbar vs limb-onset disease and FVC ≥80% vs <80%, as measured by ALS Functional Rating Score, Revised (ALSFRS-R).
Results: Following treatment, patients in both the bulbar and limb-onset groups experienced a reduction in ALSFRS-R score loss vs placebo patients through week 48. After starting edaravone, former placebo patients with either bulbar or limb-onset demonstrated a reduction in ALSFRS-R score loss from baseline to week 48, and a notable change in the slope of the ALSFRS-R score-vs-time graph. Analysis of bulbar-onset patients with either FVC ≥80% or <80% experienced a reduction in ALSFRS-R score loss vs placebo patients. In this report, no unexpected safety signals were seen, nor any inconsistencies with those of Study 19.
Conclusions: This analysis seems to indicate that ALS patients with bulbar-onset disease receive a significant benefit from initiating edaravone treatment regardless of whether they have baseline FVC ≥80% or <80%. The limitations inherent with post hoc analyses should be considered when interpreting these results.